What is fatty liver disease?

In some cases, steatohepatitis develops into cirrhosis. Excess alcohol is a common cause of fatty liver disease but there are various other causes. Fatty liver disease treatment depends on the cause and the severity of the condition.

Fatty liver disease covers a range of conditions where there is a build-up of fat in the liver cells. The liver cells (hepatocytes) normally contain some fat and related fatty chemicals (triglycerides, fatty acids, etc). Excess fat is normally passed out of liver cells, into the bloodstream, and then taken up and stored in fat cells (adipose cells) throughout the body.

In fatty liver disease, excess fat builds up in liver cells. This is thought to happen if there is some problem or disruption in the normal processing of fat and related fatty chemicals in the liver cells. (Eating fatty food by itself is not a cause of fatty liver disease.)

Simple fatty liver (NAFLD)

Simple fatty liver is fairly common and occurs when the fat content inside liver cells makes up more than 5-10% of the liver’s weight. Simple fatty liver is not associated with serious damage or harm to the liver. It seems that the fat just builds up harmlessly in liver cells. It can occur for no apparent reason. However, most people with simple fatty liver have other conditions where fatty liver is a complication.

These mainly include:

Drinking too much alcohol. Many cases develop in people who drink more alcohol than the recommended limits. Over half of people who drink heavily develop simple fatty liver.

Diabetes.

Obesity. Most people with simple fatty liver who do not drink excess alcohol are obese. The factors that determine who will develop fatty liver are not known. Some mildly overweight people develop fatty liver while some who are severely obese do not.

There are usually no symptoms caused by the fatty liver itself. However, the cause of the fatty liver such as alcohol excess, diabetes, etc, may cause other symptoms. The liver may enlarge and cause mild pain over the liver area. An enlarged liver may be felt on examination.

Steatohepatitis

In this condition the excess fat in the liver cells is associated with, or may cause, inflammation of the liver. This is called steatohepatitis (steato means fat, and hepatitis means inflammation of the liver). This is much less common than simple fatty liver. Any form of persistent hepatitis, including steatohepatitis, may eventually cause cirrhosis of the liver.

There are two types of steatohepatitis:

- Alcoholic steatohepatitis.
This is caused by drinking too much alcohol. Unless alcohol drinking is stopped it often progresses to cause cirrhosis.

- Non-alcoholic steatohepatitis (‘NASH’). This is a steatohepatitis which is not caused by alcohol. The reason why NASH develops is unclear. No cause can be found in some cases, but in some cases it seems to develop as a complication of various problems, mainly:

Diabetes.

Following jejunoilial bypass surgery for obesity

High lipid levels in the bloodstream (hyperlipidaemia)

In people who change weight relatively quickly (such as after a ‘crash diet’)

Obesity

Most people with NASH have no symptoms but may feel generally tired or have a nagging persistent pain in the upper right part of the abdomen, over an enlarged liver. In a small number of people with NASH who develop cirrhosis, symptoms of cirrhosis may develop several years after NASH first develops.

Acute fatty liver of pregnancy

This is a rare, but serious condition of pregnancy. In this condition a lot of fat builds up in the liver cells and causes damage quite quickly. The cause is not known. Symptoms include vomiting, abdominal pain and jaundice. Both mother and baby are at risk of dying with this condition as it can cause liver failure. The condition usually develops towards the end of pregnancy. The treatment is to deliver the baby as soon as possible after the condition is diagnosed.

How is fatty liver disease diagnosed?

The first sign would become apparent following routine blood tests, when liver function tests show abnormalities. Following that an ultrasound and/or fibroscan is normally performed which can show any scarring.

What is the treatment and outlook?

Fatty liver usually causes few problems but it can progress. If the patient is overweight, then lifestyle changes such as increased exercise, a well balanced diet and weight loss will normally be enough to revert the liver function tests to normal. It is always advisable to reduce or stop alcohol intake altogether and to maintain good diabetic control if appropriate.
Simple fatty liver usually causes no problems and rarely progresses. However, as mentioned, it can be a ‘marker’ for heavy alcohol consumption, which if continued, can cause serious problems. Simple fatty liver may reverse and by cutting out alcohol (if alcohol is the cause), with weight loss (if obese), or with good control of diabetes (if diabetes is the cause).

For NASH the treatment is to stop drinking alcohol as drinking will aggravate the liver. This will not stop the inflammation but will obviously help to stop progression. However, cirrhosis and serious liver problems can occur.